KR20000044037A - Method and apparatus for reducing noise in electronic film development - Google Patents

Abstract

PURPOSE: A method and an apparatus for electronic film development is provided to reduce noise substantially getting a developing or undeveloping image and to reduce a coherency speckle substantially in a developing image. CONSTITUTION: In electronic film development, a film is scanned multiple times by light during development. In a scan image, a coherency speckle noise getting worse for rear reflection image and contaminating a front reflection and transmitted image is caused. Any attempt to remove speckle effect by differencing an image made with the pre-expanded emulsion(308) from the expanded emulsion(320) can make the speckle effect worse by overlaying two different speckle pattern. A method and apparatus for electronic film development reduces the amount of coherency speckle detected by electronic film development by scanning substrate bearing a latent image and differencing that scan from the resultant post-development scan after the emulsion has expanded to its final thickness but before development has begun.

Description

METHOD AND APPARATUS FOR REDUCING NOISE IN ELECTRONIC FILM DEVELOPMENT}

Electronic film development, known as digital development, is a method of digitizing color films during the development process, as disclosed in US Pat. No. 5,519,510 to the inventors. Conversion or scanning of analog images into digital data is widely used for a variety of uses, including storing, manipulating, transmitting, displaying, and copying copies of images.

To convert the photographic image into a digital image, a film image frame is sent through a film scanning station and is illuminated along each scanline with linear light of uniform diffuse illumination typically generated by a light integrating cavity or integrator. The light transmitted through the illuminated scanline of the image frame is concentrated by the lens system onto the CCD batch image sensor, generating a three primary color light intensity signal for each image pixel. This light intensity signal is then digitized and stored. Today, film scanners that enable electronic phenomena of film come in a variety of forms, and in particular the common aspects of film image frames that digitize linear illumination and linear CCD placement based on digitizers are described in more detail in US Pat. No. 5,155,596. have.

In electronic film development, the developing film is scanned so as not to be blurred in a predetermined time period using ultraviolet rays, so that penetration of light through the predetermined anti-helization layer is increased. Some incident light is reflected from the emulsion on a milky white undeveloped silver halide containing film. Undeveloped halogen emulsions have a finite depth, over which photons from a light source are scattered and reflected. Today, this depth, commonly used in electronic film development, is in the range of the coherent length of infrared light. Due to the coherent spots, it is this limited reflection depth that causes noise in the scanned image. Noise in the scanned image captures images that are distorted into grain shapes.

Because of the longer wavelength of infrared light, both the wavelength and the divided fractional bandwidth for a fixed bandwidth contribute to a longer coherence length than is usually measured in visible light. In addition, the width of the milky silver halide layer is very thin in electronic film development, reducing the coherence length needed to produce coherent spots.

Moreover, since the image seen through the rear surface of the film is faint, as the faint image is amplified, certain coherent spots are amplified and the image is distorted. Regardless of whether light is reflected from the top or bottom of the film or transmitted through the film, this problem is evident in the scan of the film. However, due to the increased light reflected by the antihelal layer, this becomes significant in the back reflection scan. There is no prior art method mentioned for this significant problem. Generally during film processing, the dry emulsion layer across the film substrate is placed in a water bath, which causes the emulsion to expand. During electronic film processing, photons penetrating the emulsion hit particles suspended in the emulsion, re-emerge and are registered by the light sensor. As the emulsion expands, the distance between photons reflecting the particles changes proportionally. If the resulting distance difference between the photon emission paths is a quarter wavelength, the spots can change from black to white or from white to black. Therefore, a predetermined attempt is made to remove the spot effect by distinguishing the image while the emulsion is in the first extension position, and the successive second extension position can substantially reduce the spot effect by overlapping two different spot patterns. . For these reasons, coherent spots have become an important problem in carrying out the electronic film development.

In order to show coherent spots in the human eye, the path length through which light travels may be only the coherent length of the light source. Beyond the coherence length, the spots flash at the speed of light and appear to the observer as continuous. The grainy or speckled appearance of laser light as a coherent light source is due to the interference effect that is the result of coherence. Under laser light, everything in the room becomes spotty, and the spots look shiny as the light, object or observer moves.

Even under normal light conditions, spots are sometimes seen when they include very short passage differences and very narrow wide angles, such as when viewing white paper in the solar direction. For incoherent light, the coherent length belongs to the wavelength divided by the percent bandwidth. Typically, since this is a fractional wavelength of light, coherent glitter is generally not seen in the real world where non-coherent light is common.

It is therefore an object of the present invention to provide a method of electronic film development that significantly reduces noise in capturing developed or undeveloped images.

Another object of the present invention is to provide a method of electronic film development which significantly reduces or completely eliminates spots of coherence in a developed image.

It is another object of the present invention to remove noise caused by coherent spots during electronic film development, which is altered by emulsion expansion.

The present invention relates to electron phenomena of films, and more particularly to methods and apparatus for reducing noise in electronic film development.

1 is a cross-sectional view of a film layer structure exposed to light to which the method of the present invention can be applied;

2 is a cross-sectional view showing coherent spots in the film layer structure,

3A is a cross-sectional view of a film layer in which an electronic film development is performed before emulsion expansion;

3B is a cross-sectional view of the film layer in which the electronic film development proceeds after the emulsion expansion;

Figure 4 is a graph showing the relationship between time and emulsion expansion in the application of neutral and alkaline solutions,

5 is a graph showing the relationship between the development and the application of the emulsion phenomenon and time.

According to the present invention, the above and other objects and advantages are achieved by an electronic film developing method and apparatus, in which coherent spots and other disadvantages are reduced to become commercially visible images. A method and apparatus for reducing noise in an electronic film phenomenon of a substrate incorporating a latent image includes applying a first solution to the substrate to extend the substrate to a predetermined degree, allowing the substrate to expand to the predetermined degree, and Scan the extended substrate to generate a scan, induce development of the substrate, scan the substrate after development to generate a second scan, and image with reduced noise from the first scan and second scan information It includes generating.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the invention is shown in connection with a conventional color film having at least three different layers. FIG. 1 shows how each of the three layers of film 101 sensitive to each of red, green and blue are seen when exposed to light. During development, when the film to be developed is seen from the top, the top layer is clearly seen while the bottom layer is largely invisible by the opacity of the top layer. When viewed from the back side during development, the black layer is seen, while the other layers are mostly invisible. Finally, when viewed by the light transmitted through the film, the portion of light that penetrates all three layers is modulated by all three layers, thus including all three layers of field of view. In particular, as light source 100 in front of film 101 transmits light 104 through various layers of film 101, observer 105 from front 102 of film 101. Is first reflected light 106 from blue sensitive layer 108, with any light 110 transmitted from rear 113 of film 101 and ultimately through all layers seen by observer 112. ). When the light source 114 behind the film 101 113 transmits the light 115 through the layer, the observer 116 first sees the light 118 reflected from the red sensitive layer 120. The observer 116 also senses the reflection 122 from the anti-helization layer 124 that includes coherent spots. This coherent spot becomes image-related noise that the present invention reduces. Since the additional light 122 is reflected by the anti-helization layer 124, coherent spots have a bad effect on the back reflected image, and the coherent spots also contaminate the front reflected and transmitted image. Thus, the disappearance of coherent spots enhances all three images seen by observers 105, 112, and 116.

Figure 2 illustrates the coherent spot phenomenon in more detail in the background of the present invention. Typical light source 202 emits two photons along passages 204 and 206. These photons penetrate into the milky diffuser 208, an emulsion such as silver halide deposited on the substrate 210. Depending on the degree of opacity, the photons will penetrate any distance within diffuser 208 until they hit the particle and reflect. Photons of light traveling along passage 204 hit particles 212 and re-emerge along passage 214. Photons along passage 206 hit particles 216 and re-emerge along passage 218. In the case shown, the passages 214 and 218 reassemble at the observer 220.

When light source 202 is a source of coherent light, such as a laser, photons emitted along passages 204 and 206 interfere with each other to be synchronized with each other along the wavefront of the light. When perceived by the observer 220, if the two particles 212, 216 are considered to appear to overlap at one point, the two photons interfere with each other at the observer location 220 as waves appearing from different angles. Can be. In particular, if the total lengths of the two transverse passages 204-214 and 206-218 are distinguished from each other by an integer multiple of the wavelength of the interfering light emitted by the light source 202, the photons constructively interfere at the observer position 220. do. Thus, the electric field vector is added to generate twice the electric field and four times the power. On the other hand, if the path length is distinguished by the half-integer multiple of the light source wavelength, the two photons are destructively interfered, meaning that the electric field vector is canceled and no light is generated in the observer 220. The effect of this phenomenon over a large film surface area relative to the light source wavelength is that two coherent photons generate an average of twice the average power of a single photon. However, the point detected by the observer 220 corresponding to the image particles 212, 216 may be very bright or completely black depending on the degree of interference in the reflected light. This effect is known as a coherent spot, which causes noise to appear in current methods of electronic film development.

Reference is now made to FIGS. 3A and 3B for description of spot problems particularly relevant to electronic film development. During normal film processing, a dry emulsion layer 308 on the film 300 is placed in a bath to expand the emulsion 308. As mentioned in FIG. 3A, the light source 302 emits two photons along the passages 304, 306. This photon penetrates into the dry emulsion 308. Photons traveling along passage 304 hit the particles 312 located in emulsion 308 and reappear along passage 314. Similarly, photons along passage 306 hit particles 316 in emulsion 308 and reemerge along passage 318. In the case shown, the passages 314 and 318 gather again at the observer 321. 3B shows the expanded emulsion 320 after entering the bath. As in FIG. 3A, light source 302 emits two photons along passages 305 and 307. Photons penetrate the expanded emulsion 320. Photons along passage 305 hit particles 312 and re-emerge along passage 322, and photons along passage 307 hit particles 316 and re-emerge along passage 324. . Passages 322 and 324 gather again on observer 321. In addition, because of the expansion of the emulsion 320, the distance between photons reflecting the particles 321, 316 expands in proportion to the expansion of the emulsion 320. This results in a difference in passage length between the entire passage 304-314 of the first proton and the entire passage 306-318 carried by the second proton in the emulsion 308 in the expanded emulsion 320. This causes a larger difference between the passages 305-322 and 307-324 in Es. If the difference in distance between the particles 312 and 316 is 1/4 wavelength (typically less than 1/4000 mm in applications using infrared light), the spots may change completely from black to white or from white to black. Thus, any attempt to remove the spot effect by distinguishing an image made with an unexpanded emulsion 308 from an image made with an extended emulsion 320 may result in a spot effect by substantially overlapping two different spot patterns. Can be lowered.

After the emulsion extends to its final thickness or before its development begins, by scanning the substrate in which the latent image is embedded and distinguishing the scan from the resulting post development scan, the present invention provides for interference detected by an electronic film phenomenon. Reduce the amount of sex spots;

First, a solution is applied to the emulsion to begin the full expansion of the emulsion. 4 shows both the thickness of the emulsion, which may contribute to the spot effect, and both non-alkaline pH solutions (e.g., neutral solutions such as 7.0 pH or less, such as water) and alkaline pH solutions (pH greater than 7.0) for the emulsion and emulsion thickness. The relationship between the application of Depending on the application of the neutral pH solution at time 402, a transit time period 403 begins. The transit time, when viewed by the rear of the film, represents the time that the aqueous solution is absorbed by the front layer of the emulsion before reaching the rear. Once the liquid reaches the back of the film, film expansion begins at time 407. At time 408 the emulsion continues to expand until the final thickness 405 is reached. At time 408, the emulsion is saturated and no longer expands.

As shown in the graph, the emulsion thickness varies depending on the pH of the emulsion-expansion solution applied. Depending on the application of the alkaline pH solution at time 402, the expansion of the emulsion begins to reach its final thickness 406 at time 408. According to the present invention, the prescan of the substrate is optimized to minimize or eliminate coherent spots before the development begins or after time 408 when the final thickness of the emulsion is reached.

One suitable solution for expanding the emulsion is a developer that does not contain a developer. The staple type developer contains HC-110, manufactured by Eastman Kodak, Rochester, NY, and is diluted 1: 7. On the other hand, the emulsion expansion solution may be an activator to act as a developer by raising the pH of the solution to alkaline. Typical alkali activators dissolved in aqueous carriers include, but are not limited to, sodium sulfate and sodium carbonate.

In another embodiment of the invention, the developer comprising the developer is applied to the film emulsion. The developer reduces the silver halide crystals containing the latent image center. Suitable developers include, but are not limited to, Elon, Phenidone, and Hydroquinone, which are dissolved in aqueous carriers and are manufactured by Eastman Kodak, Agfa, and others. In this case, the prescan must be done depending on the emulsion reaching its final expansion before the actual development begins. 5 shows the relationship between the application of the developer and the development of the emulsion. Depending on the developer application at time 502, there is a specific time period called induction time before film development begins at inertia point 506. As the induction time progresses, the optical density of the emulsion increases. There may be a time when the emulsion expansion and film development phases overlap. In this embodiment, the prescan is optimally performed after the emulsion is substantially extended and before the end of the induction time 504. The prescan done at this point shows a final coherent spot pattern that is free of undesirable reduced halogenation.

If the solution applied to the emulsion is a developer having a developer, development is started immediately after reaching the developer's inertia point. If the solution applied to the emulsion does not contain a developer, there is an inconsistent long time after the film on which the scan is made is expanded. When the developer is added to the solution on the film, induction time 504 begins. After development starts, multiple scans are performed at spaced time intervals. This scan is then combined into a single post development scan, as is already known in the electronic film development technique. The present invention takes a post-development scan that includes an image and spot information, and distinguishes it pixel by pixel from prescan information that includes a spot pattern without an image. During the discrimination process, the first image and the second image are received in the computer as pixels. Each pixel has a numerical value representing the characteristics of the substrate, such as the luminance corresponding to that pixel. Corresponding pixel information in the first and second pictures is combined to result in pixel values resulting in a third picture in which the spot pattern is reduced or completely extinguished. The coupling function consists of a combination of predetermined mathematical steps and steps including division or subtraction, but is not limited thereto. In the present invention, the spot pattern may be zeroed or significantly reduced as a result of the combination of the first and second images.

In general two-component film development, typically a non-alkaline solution comprising a developer is applied first, followed by an alkali activator. However, if the order in which the chemicals are applied is changed, or if both the developer and the active agent are applied to a single solution consisting of the developer and the active agent, better results can be obtained. Combined solution approaches are more common in the art of film development.

Although the invention has been described in importance in terms of preferred embodiments, variations in the preferred configurations and methods may be used, and other embodiments than those specifically described herein may be practiced.

Claims (32)

Applying a first solution to the substrate to extend the substrate to a predetermined degree; Allowing the substrate to expand to the predetermined degree, Scanning the expanded substrate to produce a first scan, Inducing a phenomenon of the substrate, Scanning the substrate after a development induction step to generate a second scan, and And combining the first scan and the second scan to generate an image with reduced noise. The method of claim 1, wherein the first solution comprises a developer and an activator. The method of claim 1 wherein the first solution is a non-alkali pH solution. The method of claim 1, wherein the first solution comprises an alkaline solution. The method of claim 1, wherein the first solution comprises an alkali activator. The method of claim 1, wherein the first solution comprises a developer. The method of claim 1, wherein the substrate is configured with an emulsion comprising particles that cause spot interference. The method of claim 1, wherein the predetermined degree represents final diffusion of the substrate. 10. The method of claim 8, wherein the first scan occurs before substantial development of the substrate or after the final diffusion is substantially reached. 3. The method of claim 2, wherein said first solution causes induction of emulsion expansion and development. 8. The method of claim 7, wherein said developing inducing step comprises applying a second solution to said substrate prior to said second scan. The method according to claim 11, wherein the second solution comprises a developer. The method of claim 11 wherein the second solution comprises an active agent. 12. The method of claim 11, wherein the predetermined degree is indicative of a final extension of the substrate and occurs after the last extension is reached while the first scan is at the end of the induction time. The method of claim 1, wherein said second scanning step comprises the step of generating a plurality of scans during development. 16. The method of claim 15, further comprising combining the multiple scans into a single post development scan. 2. The method of claim 1 wherein the first and second scans read quantized pixel information indicative of the luminosity received from the substrate. 18. The method of claim 17, wherein said combining step comprises the step of distinguishing said pixel information from said first and second scans. 19. The method of claim 18, wherein the discriminating step comprises dividing the pixel information from the second scan by the corresponding pixel information from the first scan. The method of claim 1, wherein said first scanning step occurs after said accepting step before the induction time ends. Means for applying a first solution to the substrate and allowing the substrate to expand to a predetermined degree; Means for scanning the substrate to generate a first scan, Means for inducing a phenomenon of the substrate, Means for scanning the substrate after developing induction to generate a second scan, And means for combining the first scan and the second scan to generate an image with reduced noise. 22. The apparatus of claim 21, wherein the first solution comprises a developer and an activator. 22. The apparatus of claim 21, wherein the noise results from spot interference caused by particles contained in an emulsion deposited on the substrate. 22. The apparatus of claim 21, wherein the predetermined degree represents final expansion of the substrate. The apparatus of claim 21, wherein the first solution comprises a developing solution. 22. The apparatus of claim 21, wherein said second solution is applied to said substrate to induce development prior to said second scan. 27. An apparatus according to claim 26, wherein said second solution comprises a developer. 27. The device of claim 26, wherein said second solution comprises an activator. 22. The apparatus of claim 21, wherein a plurality of scans are generated during development. 22. The apparatus of claim 21, wherein the first and second scans read quantized pixel information indicative of the brightness received from the substrate. 22. An apparatus according to claim 21, wherein said combining means is means for distinguishing said pixel information from said first and second scans. 32. The apparatus of claim 31, wherein said means for discriminating is means for mathematically dividing said pixel information from said second scan by said corresponding pixel information from said first scan.